Ms timer in slideshow (with 0ms as option)

I've asked before and will continue to ask. I really would like to see the built in viewer be changed to have a ms timer for automatic slideshows. I use opus for previewing images (for rendered animations) and would love to be able to play them at exactly 30 (or 24, or 25) frames per second. If we had ms time for the slideshow this would easily be possible.

Right now I have to hold space to rip through an image sequence but it goes WAY to fast, yet the 1 second minimum in the slideshow is FAR TOO slow.